What is amplitude in acoustics?

• A. Height of the sound wave, measured in decibels
• B. Frequency of the wave
• C. Duration of the sound
• D. Timbre of the sound

Answer: (A)

Amplitude is the height of the sound wave—the maximum displacement or pressure variation in the medium. This height determines how loud the sound is: larger amplitude means a louder sound. This concept is distinct from frequency (which affects pitch), duration (how long the sound lasts), and timbre (the quality or color of the sound). Decibels describe sound level or intensity relative to a reference, which relates to loudness but is not the definition of amplitude itself. So describing amplitude as the height of the wave best captures what amplitude is.